In a small bowl, combine the yeast, sugar, and warm water to dissolve the yeast. Combine the butter and milk, heat to melt the butter, and cool to room temperature. Beat the eggs with a wire whip until light. Add the yeast mixture and the milk-butter mixture to the eggs. Mix well. Stir in the flour with a wooden spoon to form a dough. Knead the dough by hand in the bowl for 5 minutes until it reaches an even consistency and detaches from the side of the bowl. Form the dough into a ball, sprinkle with 2 tablespoons flour, cover with a damp towel, and let rise for 1 ÃÂ½ to 2 hours or until it has doubled in volume. Butter the baba molds. Fill the molds 1/3 full with dough, cover, and let rise 1 hour. Bake at 350ÃÂ° for 25 minutes. Remove from the oven, cool 5 to 10 minutes, and then remove the babas from their molds. Brush rum syrup evenly over the babas until all the syrup has been absorbed.